Opening Day! How can you tell spring has sprung and summer is coming? The wrought iron gate to Fort Knox is open and the observatory elevator is bringing visitors up 420 feet to look out of the surrounding windows for gorgeous panoramic views of mid-coast Maine. See for yourself on May 1st as both the Fort Knox Historic Site and Penobscot Narrows Bridge Observatory (PNO) mark the Opening Day for the 2024 Season.